An overview of Centralized Radio Access Network (C-RAN) architectures—also known as Cloud Radio Access Network or distributed base station architectures—as addressed by the present invention is given in “C-RAN—The Road Towards Green RAN”, China Mobile Research Institute, White Paper, Version 2.5, October 2011. Possible C-RAN architecture options currently being considered are as shown in FIG. 1, where the C-RAN is generally referred to by reference numeral 1. Basically, in C-RAN architecture, a functional split of the base station functionality is realized between distributed access points and a centralized access controller. More specifically, the access points, according to conventional prior art terminology also denoted as radio function units or remote radio heads (RRH) 2, are separated from the base station's access controller 3, also referred to as digital function unit or baseband unit (BBU), with a backhaul link 4 between RRHs 2 and access controller 3. The advent of centralized-RAN technology enables the potential to have centralized processing of data.
In the centralized radio access network (C-RAN) of FIG. 1, base station processing is centralized at a data center 5. This (centralized) data center 5 performs part or all of the processing which is traditionally performed at the (remote) base stations, i.e. analog-to-digital conversion (in the case of “Radio over Fiber”) and digital base band processing (“Remote Radio Head”), see for reference C. Chen and J. Huang, “Suggestions on potential solutions to C-RAN by NGMN alliance,” NGMN Alliance, Tech. Rep., January 2013.
CRAN systems may either run on dedicated hardware (so called baseband pools) which deploys the same processing architecture as base stations, or they run on commodity hardware where standardized IT hardware is deployed. In both cases, but particularly in the latter case, a virtualized environment can be provided such that base stations run in virtual machines where each virtual machine receives access to part of the data center resources. The actual amount of resources which is provided may not be revealed to the virtual machine, but only a virtualized representation. The major advantage of deploying virtual machines lies in the fact that load fluctuations (in terms of processing load) can be balanced across multiple base stations and across time.